You don't need the wilderness, a crackling campfire and a bunch of overly frisky camp counselors to commune with nature. Urban camping is a real thing these days. With almost 81 percent of the U.S. population living in urban areas (according to the 2010 census), it's not likely to be going away any time soon, either.

What is it?

Urban camping is what it sounds like: camping, in some form, in an urban setting. The key to that definition, though, is "in some form." Urban camping can take many, many different forms.

A group of people camp on a roof of New York City. The group was organized by artist Thomas Stevenson, and campers are encouraged to turn off their electronic gadgets while focusing on exploring the outdoor environment within an urban setting. (Photo: Andrew Burton/Getty Images)

Artist Thomas Stevenson built some lean-tos and stuck them on the roof of a building in Brooklyn (pictured above). He invites people up, asks them to bring some food to share, suggests that they unplug and they spend a night camping, under the stars, with the twinkling lights of the big city all around them. One night. No charge.

Other camping experiences are a little more ... structured. Some cities, like Chicago, will open up vast areas of their parks to accommodate campers on specials occasions.

We could get into man's basic need to reconnect with nature, and that's probably true enough. But if that's all these urban campers are after, the Grand Tetons, rather than that parking lot just off Grand Avenue, are probably the better choice.

Whether that's moral — denying a homeless person a place to sleep and the right to be near needed services — is another question. But one-night or over-the-weekend urban campers sometimes face similar restrictions. Loitering is a law on the books everywhere, too.

Generally, it's illegal just about everywhere to camp out on public property without a permit. You need permission on private property, too. Urban campers do it anyway, all the time. Do so at your own risk.

Is it safe?

If you take precautions, camping in the big city can be nearly as safe as camping in Big Sur. But it is the big city. As any city dweller knows, you have to have your wits about you.

So don't camp alone. Know the area. Let friends know where you are. Make sure your little slice of city heaven has plenty of light.

And, if you're camping on a roof, as artist Stevenson points out on his site, don't forget that: "you are on a roof/be very mindful of the edge."